Telephone system



Sept. 2 1924. 1,506,899

C. L. GOODRUM TELEPHONE SYSTEM Filed April 20. 1920 Affy.

Patented Sept. 2, 1924.

UNITED STATES 1,506,899 PATENT OFFICE.

CHARLES L. GOODRUM, OF NEW YORK,

N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Application filed April 20, 1920. Serial N0. 375,205.

To all whom it may concern.

Be it known that I, CHARLES L. GOODRUM, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone systems and particularly to means for automatically connectinga calling line to an idle trunk.

The object of the invention is to provide a simple and eflicient arrangement free from mechanical contrivances for rapidly preselecting and allotting idle trunks in that type of switching mechanism now generally known as the cross-bar switch.

In accordance with this object, each trunk bar magnet has associated with it an auxiliary relay whose function it is to cause the energization of the trunk bar magnet when it becomes first in order and immediately, that the associated trunk is seized, to extend the starting wire to the trunk bar magnet next in order.

A feature of the invention is the use of the line and trunk bar conductors as the means for energizing the starting circuit whereby the line relays are made independent of the circuit for the trunk bar relays and magnets.

The drawing is a diagrammatic illustration of a means for carrying out the present invention.

The drawing shows two of a plurality of line bars 1 and 2, which are individual respectively to lines 3 and 4. Line bar 1 carries a plurality of sets of multiple contact members 5, 6 and 7. In a similar manner, line bar 2 carries a plurality of sets of multiple contact members 8, 9 and 10. By means of pivots 11 and 12, line bar 1 is rotatably mounted in the frame of the apparatus and is normally moved toward the right by means of a spring 13 coiled around the pivot 12. This line bar is controlled by a magnet 14, which has an armature 15 whose function it is to bear on the pivot 12 and move the line bar toward the left. By means of a cam 16 cooperating with a pin 17, the line bar is rotated in a counter clock-wise direction.

Three of a plurality of trunk bars are chime, 18, 19 and 20: These are, in a aimilar manner, rotatably mounted in the frame. Trunk bar 18 carries a plurality of sets of multiple contact members, one of which is shown numbered 21. Similarly, the trunk bar 19 carries a plurality of sets of multiple contact members, two of which are shown, Nos. 22 and 23. Contact members 21 of trunk bar 18 cooperate with multiple contact members 5 of line bar 1 and multiple contact members 23 of trunk bar 19 cooperate with multiple contact members 9 of line bar 2. Magnets 24 and 25 control, respectively, trunk bars 18 and 19. The energization of either of these magnets causes the rotation in a clockwise direction of its associated trunk bar.

As shown in the drawing, trunk bar 19 has been rotated. Its multiple contact members 23 have been engaged by the multiple contact members 9 of the line bar 2 and the trunk bar 19 has been reset in its normal position, wherein its other multiple contact members, such as 22, are in a position where they will not be engaged by any multiple contact members individual to any of the other line bars.

Associated with the trunk bar magnet 24, there is a relay 26 and associated with the trunk bar magnet 25 there is a relay 27. If relay 27 may be considered as the first in series, it has a ground connected to its armature. Through its back contact it extends the ground to the magnet 25 but, when energized as shown in the drawing, it extends the ground through its front contact, a pair of contacts controlled by the magnet 25 and thence to the armature of relay 26, where it is further extended through the back contact of relay 26 to the winding of magnet 24, thus causing the energization of magnet 24.

It will be assumed that the line 3 initiates a call. Thereupon a line relay 28 will be energized through a circuit includin its windings, a pair of contacts controll by the left-hand armature of magnet 14 and the loop of the subscribers line 3. vRelay 28 becomes energized in this circuit and through its armature places a ground on the right-hand windings of magnet 14 to battery and ground. Magnet 14 attracts both of its armatures' when energized in this circuit. Since trunk bar magnet 24 is energized, an since its multiple contact members 21 are in a position to be en a d by the multiple contact members 5 o. t line bar 1, the airergization of magnet 14 causes the counter clock-wise rotation of line bar 1 and the enagement of the said contact members. Thereupon, the subscribers line 3 15 extended through the multiple contact members 5 and 21 to the trunk 29. The seizure of trunk 29 causes the energization of a relay 30 which, in turn, causes the energization of a slow-to-release relay 31. Relay 31, through its armature places a ground on the third conductor 32 of the trunk 29, which is extended through the multiple contact members 21 and 5 to conductor 33, and thence through the left-hand windings of magnet 14 to battery and ground. Through this circuit, magnet 14 is held in its energized position. At the same time, a multiple circuit through the winding of relay 26 is established whereby relay 26 moves its armature to its attracted position, thereby cutting off magnet 24 and extending the starting circuit through the contacts controlled by magnet 24 to the wire 34, which extends to the next in order trunk bar magnet. The energization of magnet-14 cutsofi the line relay 28 from line 3, thereby opening the original circuit for the magnet 14 but, as before stated, magnet 14 is held in its energized position through the energization of its left-hand windings.

Since further extension of the call through the trunk 29 forms no part of the present invention, it will not be further described. At the end of the conversation, when the subscriber on line 3. replaces his receiver on its hook, relay 30 and in turn relay 31 are deenergized. The ground is removed from conductor 32 and relay 26, and magnet 14 becomes deenergized. Thereupon the apparatus restores to its normal position.

On a call incoming to line 3, a ground is placed on conductor 33 in the usual manner and the left-hand windings of magnet 14 are energized. This causes the attraction of the left-hand armature of magnet 14 only, whereby the contacts controlled by this lefthand armature are actuated and the possibility of energizing the right-hand'windings is eliminated.

What is claimed is:

1. In a telephone system, telephone lines, a line relay, a line bar, and a combined line bar magnet and cut-off Ifelay associated with each line, trunk lines for extending said lines, a trunk bar, a trunk bar magnet and an auxiliary relay associated with each.

trunk, an allotter circuit for said trunks independent of said line relays and said cornbined line bar magnets and cut-ofl' relays for placing idle trunks in condition for seizure by said lines through the agency of said line and trunk bars, and means for directly controlling said allotter circuit over said line and trunk bars.

2. In a telephone system, a cross bar switch comprising a plurality of line bar magnets, a plurality of trunk bar magnets, a relay associated with each of said trunk bar magnets, means controlled by said relays for holding one of said trunk bar magnets energized, means for energizing one of said line bar magnets, means controlled by said energized line bar magnet and said energized trunk bar magnet for energizing the relay associated with said trunk bar magnet.

3. In a telephone system, a cross bar switch comprising a plurality of line bar magnets, a plurality of trunk ba-r magnets, a relay associated with each of said trunk bar magnets, means controlled by said relays for holding a single one of said trunk bar magnets energized, and means controlled by said line bar magnets for energizing said relay associated with saidenergized trunk bar magnet.

4. In. a telephone system, a cross bar switch comprising a plurality of line bar magnets, a plurality of trunk bar magnets. a relay associated with each of said trunk bar magnets, means controlled by said relays for holding a single one of said trunk bar magnets energized, means controlled by said line bar magnets for energizing said relay associated with said energized trunk bar magnet, and means controlled by said energized relay for deenergizing said energized trunk bar magnet and energizing the next in order of said trunk. bar magnets.

5. In a telephone system, a cross bar switch comprising a plurality of line bar magnets. a. relay associated with each line bar magnet, a plurality of trunk bar magnets, a relay associated with each of said trunk bar magnets, means controlled by said last relays for holding one of said trunk bar magnets energized, means controlled by said relays associated with said line bar magnets for energizing said associated line bar magnets, means controlled by an energized line bar magnet and an energized trunk bar magnet for energizing said relay associated with said energized trunk bar magnet, and means controlled by said last relay for deenergizing said associated trunk bar magnet and causing the energization of the next in turn of said trunk bar magnets.

In witness whereof, I hereunto subscribe my name this 16th day of April A. D., 1920.

CHARUES L. GOODRUM. 

